1. Field of the Invention
The invention relates to a combination driving hub for bicycle, especially to the hub being able to be driven by a combination force of a motor and a bicycle rider.
2. Description of Related Art
In some countries bicycles are more used as vehicles than as a sporting utility. A large number of people often use bicycles in daily life. Recently a kind of electric motor bicycle has been developed to help bicycle riders to save their labor. However, this kind of electric motor bicycle can only be propelled by either an electric motor or by pedaling of the rider. If the electric motor and the foot power are employed simultaneously, force from the pedaling may destroy a driving system of the electric motor. Therefore, when a larger force, for example in climbing a slope, or a greater speed is needed, which could be obtained by a combined propulsion of the electric motor and pedaling, it will be beyond the above conventional electric motor bicycle.